GB/T 11376-2020.Metallic and other inorganic coatings-Phosphate conversion coating of metals.
1 Scope
GB/T 11376 specifies the method for determining the requirements of phosphate coatings.
GB/T 11376 is applicable to ferrous metals, aluminum, zinc, cadmium and their alloys (see Appendix A).
2 Normative references
The following documents are indispensable for the application of this document. For any dated referenced document, only the dated version applies to this document. For any undated referenced document, the latest version (including all amendments) applies to this document.
GB/T 3138 Terminology for surface treatment of metals and other inorganic coatings (GB/T 3138-2015, ISO 2080: 2008, IDT)
GB/T 4955 Metallic coatings - Measurement of coating thickness - Coulometric method by anodic dissolution (GB/T 4955-2005, ISO 2177:2003, IDT)
GB/T 4956 Measurement of coating thickness of non-magnetic coatings on magnetic substrates - Magnetic method (GB/T 4956-2003, ISO 2178:1982, IDT)
GB/T 9792 Conversion coatings on metallic materials - Determination of coating mass per unit area - Gravimetric method (GB/T 9792-2003, ISO 3892: 2000, MOD)
GB/T 10125 Artificial atmosphere corrosion test Salt spray test (GB/T 10125-2012, ISO 9227: 2006, IDT)
GB/T 12609 Sampling procedure for inspection of electrodeposited metallic coatings and related finishes by counting (GB/T 12609-2005, ISO 4519: 1980, IDT)
GB/T 16921 Metallic coatings - Measurement of coating thickness - X-ray spectrometry (GB/T 16921-2005, ISO 3497: 2000, IDT)
ISO 27830 Guide to the standardization of metallic and other inorganic coatings (Metallic and other inorganie coatings-Requirements for the designation of metallic and inorganic coatings)
This standard specifies the method for determining the requirements for phosphate coatings. This standard applies to ferrous metals, aluminum, zinc, cadmium and their alloys (see Appendix A).

ICS25.220.20
National Standard of the People's Republic of China
GB/T11376—2020
Replaces GB/T11376—1997
Metallic and other inorganic coatings
Metal phosphate coating
Metallic otherinorganiccoatings-Phosphateconversioncoatingofmetals(ISO9717:2017,MOD)
2020-06-02Release
State Administration for Market Regulation
National Administration of Standardization
Release
2021-04-01Implementation
Foreword
Introduction
Scope
Normativereferenceddocuments
Termsanddefinitions
Informationtobeprovidedbythepurchasertothesupply
Typeandmarkingofphosphatecoating
Phosphate Types of phosphate coating
Marking of phosphate coating
Phosphate coating
Appearance
Weight per unit area of ??phosphate coating
Post-treatment
Thickness of phosphate coating
7 Heat treatment
Appendix A (Informative Appendix)
Appendix B (Informative Appendix)
Appendix C (Normative Appendix)
References
General information
Identification of phosphate coating
Determination of neutral salt spray resistance of phosphate coating
GB/T11376—2020
Foreword
This standard was drafted in accordance with the rules given in GB/T1.1-2009. GB/T11376—2020
This standard replaces GB/T11376—1997 "Phosphate conversion coating of metals". Compared with GB/T11376-1997, the main technical changes of this standard are as follows:
Modified "Normative Reference Documents" (see Chapter 2, Chapter 2 of the 1997 edition); added "Terms and Definitions" (see Chapter 3); modified "Information to be provided by the purchaser to the supplier" (see Chapter 4, Chapter 3 of the 1997 edition); modified "Types and markings of phosphate coatings" (see Chapter 5, Chapter 4 of the 1997 edition); modified "Phosphate coatings" (see Chapter 6, Chapter 6 of the 1997 edition); -Modified the appendix;
Added "References".
This standard adopts ISO9717:2017 "Phosphate conversion coatings of metals and other inorganic coatings" by redrafting method.
The technical differences between this standard and ISO9717:2017 and their reasons are as follows: Regarding normative references, this standard has made technically different adjustments to adapt to my country's technical conditions. The adjustments are concentrated in Chapter 2 "Normative References". The specific adjustments are as follows: · Replace ISO2080 with GB/T3138, which is equivalent to the international standard (see Chapter 3); · Replace ISO2177 with GB/T4955, which is equivalent to the international standard (see 6.4); · Replace ISO2177 with GB/T4955, which is equivalent to the international standard (see 6.4); GB/T4956, which is equivalent to the international standard, replaces ISO2178 (see 6.4); GB/T9792, which is modified to adopt the international standard, replaces ISO3892 (see 6.2); GB/T10125, which is equivalent to the international standard, replaces ISO9227 (see 6.3); GB/T12609, which is equivalent to the international standard, replaces ISO4519 (see Chapter 4); GB/T16921, which is equivalent to the international standard, replaces ISO3497 (see 6.4). This standard has made the following editorial changes:
The numbers of Appendix A, Appendix B, and Appendix C have been adjusted in the order mentioned in the text of the standard. This standard was proposed by the China Machinery Industry Federation. This standard is under the jurisdiction of the National Technical Committee for Standardization of Metallic and Non-metallic Coatings (SAC/TC57). The drafting units of this standard are: Wuhan Institute of Material Protection Co., Ltd., Wuhan Material Protection Surface New Materials Co., Ltd., Zhaoqing College, Hexing Automotive Electronics Co., Ltd., Wenzhou Ruiming Industrial Co., Ltd., and Foshan Kefu Technology Co., Ltd. The main drafters of this standard are: Li Xinli, Zhong Ping, Su Hui, Yi Juan, Wu Xiaosong, Zeng Huan, Yuan Xing, Xia Jingzhong, Xu Chaoyu, Tan Wuyong, Lin Juan, Zhou, He Dedao, Li Ni, Lu Yang.
The previous versions of the standards replaced by this standard are: GB/T11376-1989, GB/T11376-1997.
GB/T11376-2020
Introduction
Phosphate coating is applied to ferrous metals, aluminum, zinc, cadmium and their alloys (including galvanized steel sheets and galvanized alloy steel sheets). It can be used as the final finishing layer or as an intermediate layer of other covering layers. Its functions are: to enhance corrosion resistance;
to improve the adhesion between the substrate and the coating or other organic finishing layers; to improve the cold processing properties of the material, such as wire drawing, tube drawing, extrusion, etc.; to improve the surface friction properties to promote its sliding. Phosphate film can be obtained by treating with a solution with dihydrogen phosphate as the main component. Phosphate film is mainly used for ferrous metals and zinc. The following factors will affect the unit area mass and apparent density of the phosphate film: the material and surface condition of the workpiece;
early mechanical and chemical treatment methods, etc.; the phosphating process used.
All phosphate films have pores to a greater or lesser extent, but they can basically be sealed by subsequent sealing processes. IN
Metal and other inorganic coverings
Phosphate film of metal
GB/T11376—2020
Warning-Some substances and processes required by this standard may cause health hazards if appropriate measures are not taken. This standard does not discuss any health hazards, safety or environmental issues involved in the use process. The developers, purchasers and/or users of this standard are responsible for establishing appropriate and feasible health, safety and environmental regulations and taking appropriate measures 1 Scope
This standard specifies the method for determining the requirements for phosphate films. This standard applies to ferrous metals, aluminum, zinc, cadmium and their alloys (see Appendix A). 2 Normative references
The following documents are indispensable for the application of this document. For any dated referenced document, only the dated version applies to this document. For any undated referenced document, the latest version (including all amendments) applies to this document. GB/T3138 Terminology for surface treatment of metals and other inorganic coatings (GB/T3138—2015, ISO2080:2008, IDT) Metallic coatings Measurement of coating thickness
GB/T4955
2003.IDT)
GB/T4956
Non-magnetic coating on magnetic substrate
ISO2178:1982, IDT)
GB/T9792
Conversion film on metal materials
ISO3892:2000MOD)
GB/T10125
GB/T12609
Anodic dissolution coulometric method (GB/T4955—2005, ISO2177: Measurement of coating thickness
Magnetic method (GB/T4956—2003, || tt||Determination of film mass per unit area
Weight method (GB/T9792-2003,
Artificial atmosphere corrosion test
Salt spray test (GB/T10125-2012, ISO9227:2006, IDT)Sampling procedure for counting inspection of electrodeposited metal coatings and related finishing (GB/T12609-2005, ISO4519:1980, IDT)
GB/T16921
2000.IDT)
Metallic coating
Coating thickness measurement X-ray spectrometry (GB/T16921-2005, ISO3497: ISO27830Metallic and other inorganic coatings—Requirements Guide (Metallic and other inorganic coatings—Requirements Guide) 3 Terms and definitions
The terms and definitions defined in GB/T 3138 apply to this document. The addresses of the terminology databases for standardization maintained by ISO and IEC are as follows: IEC electronic open platform: http://electropedia.org/; -ISO online browsing platform: http://iso.org/obp. 4 Information that the purchaser shall provide to the supplier
The purchaser shall provide the following information:
GB/T11376—2020
Description of the phosphate coating as specified in this standard (see 5.2). For steel parts with a tensile strength of not less than 1000MPa, or workpieces with local surface hardening, cold forming or welds, it is very important to eliminate hydrogen embrittlement. Phosphating should be carried out after eliminating hydrogen embrittlement; the supply and demand parties shall negotiate technical measures to minimize the risk of hydrogen embrittlement. No heat treatment can guarantee the complete elimination of hydrogen embrittlement. The supplier shall explain the sampling procedure selected for the heat treatment process used, the required qualified quality level or any other requirements and tests that are different from GB/T12609. Surface treatment or phosphating.
Surface appearance.
Corrosion resistance.
The properties, appearance and state of the base metal that affect the film formation and/or appearance of the phosphate coating. When applicable, technical measures to minimize the risk of hydrogen embrittlement according to user requirements. Types and markings of phosphate films
Types of phosphate films
Types of phosphate films are shown in Table 1.
Table 1 Types of phosphate films
Elements detected
Fe(I)
Zn(Ca-free)
Zn and Ca
Types and symbols of phosphate films
Feph
Mnph
Znph
ZnCaph
There are also improved zinc phosphate films formed by adding iron and/or nickel and/or manganese. The improved metals usually exist in the form of complex salts, such as ZnzMe(PO). ·4H,O, where Me represents iron (I), nickel or manganese. Zinc is the main metal element of improved zinc phosphate films. In order to avoid confusion, this type of film is not separately marked. Note: The metal in the base material will participate in the film formation. The types and characteristics of phosphate films can be found in Appendix A, and the identification methods of phosphate films can be found in Appendix B. 5.2
Marking of phosphate coating
The marking of phosphate coating shall consist of the following information: a)
This standard number “GB/T11376” and “_” for “phosphate coating”.
The marking of the base material shall be the chemical symbol of the base material (or the chemical symbol of the main alloying element). Slash “/”.
The type symbol of the phosphate coating.
Slash “/”.
Symbols indicating the purpose of the phosphate coating:
Electrical insulation;
Reducing friction (promoting sliding);
Improving adhesion and/or enhancing corrosion resistance:
Promoting cold forming.
h) Slash “/\.
Indicates the mass of the phosphate coating layer per unit area, unit: g/m, error: ±30%. If the phosphate coating is post-treated, the following information shall be added to the marking: j) Slash “/”.
k) indicates the symbol for post-treatment of the phosphate coating (see Table 2). If necessary, additional information shall be marked according to the following principles: GB/T11376—2020
The slash "/" is used to separate data fields in the mark. Double separators or multiple slashes indicate that a step in this process is not required or has been deleted (see ISO27830).
Phosphate coating
6.1 Appearance
Zinc phosphate coating, zinc calcium phosphate coating and manganese phosphate coating shall be evenly covered on the metal surface, free of white residue, corrosion products or fingerprints. Note: Differences in the surface of the base material or around the hanging point that contacts the hanger during the phosphating process. Slight changes in appearance are common and cannot be a reason for rejection.
Weight per unit area of ??phosphate film
Weight per unit area of ??phosphate film shall be measured in accordance with the provisions of GB/T9792 6.3 Post-treatment
Appropriate post-treatment can improve the corrosion resistance of phosphate film. The symbols of post-treatment of phosphate film are shown in Table 2. 2 Symbols of post-treatment of phosphate film
Table 2
Symbol
Type of post-treatment of phosphate film
Apply varnish or organic coating, inorganic or non-film-forming organic sealant Apply inorganic or organic sealant
Apply dye
Apply oil, grease or other lubricant
Apply wax
Apply soap
Test the corrosion resistance of the post-treated workpiece according to the corrosion test specified by the purchaser. If the test method is not specified, the test shall be carried out in accordance with the neutral salt spray test (NSS) described in GB/T10125 and Appendix C. The contracting parties shall determine the salt spray test cycle through consultation. The shortest test period for the first appearance of corrosion products specified by the purchaser should be met. The zinc phosphate film Znph used on ferrous metals has the function of enhancing corrosion resistance, and the unit area mass is 3g/m±0.9g/m2. It is successively post-treated with a sealant (T2) and a coating (T1). The marking is as follows: Phosphate film GB/T11376-Fe/Znph/r/3/T2/T16.4 Phosphate film thickness
The thickness of the phosphate film can be measured by the following methods: Dissolution method, measured according to the provisions of GB/T4955; Magnetic induction method, measured according to the provisions of GB/T4956: 33 Post-treatment
Appropriate post-treatment can improve the corrosion resistance of phosphate film. The symbols of phosphate film post-treatment are shown in Table 2. 2 Symbols of phosphate film post-treatmentbZxz.net
Table 2
Symbol
Type of phosphate film post-treatment
Apply varnish or organic coating, inorganic or non-film-forming organic sealant Apply inorganic or organic sealant
Apply dye
Apply oil, grease or other lubricant
Apply wax
Apply soap
Test the corrosion resistance of the post-treated workpiece according to the corrosion test specified by the purchaser. If the test method is not specified, the neutral salt spray test (NSS) described in GB/T10125 and Appendix C shall be used for the test. The salt spray test cycle shall be determined by negotiation between the two parties to the contract. The shortest test cycle for the first appearance of corrosion products specified by the purchaser shall be achieved. The zinc phosphate film Znph used on ferrous metals has the function of enhancing corrosion resistance. The mass per unit area is 3g/m±0.9g/m2. It is successively post-treated with a sealant (T2) and a coating (T1). The marking is as follows: Phosphate film GB/T11376-Fe/Znph/r/3/T2/T16.4 The thickness of the phosphate film
The thickness of the phosphate film can be measured by the following methods: Dissolution method, measured according to the provisions of GB/T4955; Magnetic induction method, measured according to the provisions of GB/T4956: 33 Post-treatment
Appropriate post-treatment can improve the corrosion resistance of phosphate film. The symbols of phosphate film post-treatment are shown in Table 2. 2 Symbols of phosphate film post-treatment
Table 2
Symbol
Type of phosphate film post-treatment
Apply varnish or organic coating, inorganic or non-film-forming organic sealant Apply inorganic or organic sealant
Apply dye
Apply oil, grease or other lubricant
Apply wax
Apply soap
Test the corrosion resistance of the post-treated workpiece according to the corrosion test specified by the purchaser. If the test method is not specified, the neutral salt spray test (NSS) described in GB/T10125 and Appendix C shall be used for the test. The salt spray test cycle shall be determined by negotiation between the two parties to the contract. The shortest test cycle for the first appearance of corrosion products specified by the purchaser shall be achieved. The zinc phosphate film Znph used on ferrous metals has the function of enhancing corrosion resistance. The mass per unit area is 3g/m±0.9g/m2. It is successively post-treated with a sealant (T2) and a coating (T1). The marking is as follows: Phosphate film GB/T11376-Fe/Znph/r/3/T2/T16.4 The thickness of the phosphate film
The thickness of the phosphate film can be measured by the following methods: Dissolution method, measured according to the provisions of GB/T4955; Magnetic induction method, measured according to the provisions of GB/T4956: 3
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